Ken Kesey simply wasn't this hot.
It was Tom Wolf's 1968 book "The Electric Kool-Aid Acid Test" about the Merry Pranksters which forever cemented the popular association between hippies and living in school buses. And as we can see from this video, they're still at it. Now, to be fair, the conversion of this bus from school transport to mobile home was actually pretty respectable, much more so than just ripping out the seats and throwing in some mattresses and bean bag chairs.
You will have to listen to your tour guide saying annoying hippie crap, but it'll be pretty easy to find something else to concentrate on.